title: Strain differences in guinea pigs' bronchial sensitivity to acetylcholine.
abstract: The bronchial sensitivity to acetylcholine (ACh) of guinea pigs of various strains was investigated to clarify strain differences. Inbred Strain 2, Strain 13 and JY-1 and non-inbred Hartley strain (two colonies) were used in this experiment. (1) Guinea pigs were exposed to 0.08% ACh aerosol and the time needed to produce falling down (TNPFD) was determined. Mean +/- standard error of TNPFD (n = 14 per group) of animals was 182 +/- 28 sec, 148 +/- 22 sec, 210 +/- 30 sec, 342 +/- 24 sec and 406 +/- 36 sec in Strain 2, Strain 13, JY-1, Hartley (Japan SLC) and Hartley (Hitachi), respectively. There was a significant difference in TNPFD between inbred strains and non-inbred strains (P less than 0.05 or P less than 0.01), indicating that inbred strains had higher sensitivity. (2) Guinea pigs were exposed to 20-5000 micrograms/ml ACh for 2 min. The mean dose threshold as determined by transcutaneous oxygen pressure was 524 micrograms/ml, 424 micrograms/ml, 614 micrograms/ml, 1317 micrograms/ml and 1651 micrograms/ml (n = 14 per group) in Strain 2, Strain 13, JY-1, Hartley (Japan SLC) and Hartley (Hitachi), respectively. Inbred strains showed lower dose thresholds than non-inbred strains. (3) Isolated trachea-lungs of 5 guinea pigs were perfused with 10(-9)-10(-5) g/ml ACh to determine strain differences. Dose response curves of animals of inbred strains shifted to the left (lower concentrations), unlike those of non-inbred strains, suggesting that inbred strains had higher sensitivity to ACh than non-inbred strains.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Institute of Bio-Active Science, Nippon Zoki Pharmaceutical Co., Ltd., Hyogo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Mikami
authors.forename: R
authors.initials: R
authors.lastname: Nishibata
authors.forename: Y
authors.initials: Y
authors.lastname: Kawamoto
authors.forename: T
authors.initials: T
authors.lastname: Ino
mesh_terms: D000109:Acetylcholine / Q000276:immunology*; D000818:Animals; D001249:Asthma / Q000276:immunology; D001980:Bronchi / Q000276:immunology*; D001985:Bronchial Provocation Tests; D004195:Disease Models, Animal; D004306:Dose-Response Relationship, Immunologic; D006168:Guinea Pigs / Q000276:immunology*; D066298:In Vitro Techniques; D007178:Inbreeding
chemical_list: D000109:Acetylcholine